[Octave-bug-tracker] [bug #52193] Font choices are ignored when printing to an image file

[Rik]

Update of bug #52193 (project octave):

                 Release:                   4.2.1 => dev                    

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Follow-up Comment #21:

I think a reasonable way to obtain svg output, and handle the artifacts, may
be to use a separate program (svg2svg) which just does polygon reconstruction,
and then a separate Qt program to change svg2any_format.

I reviewed octave-svgconvert.cc which was a hodge-podge of C, C++, and Qt
styles (printf as well as std::cerr as well as QDebug).  I modified things to
follow Octave coding conventions, but it is still not perfect.  It is
attached.

The issue that I encounter with thin hairlines is triggered when the svg file
contains multiple polygons in a row, but they are not necessarily related. 
The algorithm in octave-svgconvert.cc is too simple and only checks for
whether the colors of the polygon are the same before trying to merge them. 
The attached bar.svg was generated by gl2ps for a stacked bar graph.  It has
polygons (rectangles) which are physically separated, but which appear next to
each other in the svg and so are merged.  I believe it is necessary to put an
additional check that two polygons to be merged have at least one vertex in
common.

I started writing a polygon reconstruction script in Perl (svg2svg).  I've
made good progress.  The svg is so simple that regular expressions suffice to
do the processing rather than using a full xml interpreter.  But the merging
of polygons is more difficult than I thought and I don't have the time to work
on this just now.

I propose that this bug be a topic that we take up during one of the code
sprints during OctConf 2018 in 4 weeks.



(file #43273, file #43274)
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Additional Item Attachment:

File name: octave-svgconvert.cc           Size:18 KB
File name: bar.svg                        Size:12 KB


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